Imported model bones not working
What you can see are the relation lines, not the bones. For some reason your bones are so tiny, you can't see them. Select the armature, go to edit mode, select Individual Origins for Pivot point, then hit "a" to select everything. (If you selected everything the Gizmo must be appear in the middle of the skeleton). Then hit "s" to scale and type in a big number (500,000). Then hit enter or left click and go back to pose mode.